1. Field
The present invention relates to detecting the current operation mode of vehicles for the purposes of vehicle emission control, including the operating mode of hybrid vehicles such as, but not restricted to, hybrid electric vehicles (HEVs).
2. Description of the Related Art
Conventional motor vehicles such as cars and trucks employ an internal combustion engine (ICE) running on petrol or diesel fuel. By contrast, hybrid vehicles use a mixture of power or fuel sources. A subclass of hybrid vehicles is the hybrid electric vehicle, or HEV. Hybrid vehicles use an electric motor, powered by a battery and/or by a generator, in addition to the ICE. So-called “full” hybrids can operate on fuel by running the internal combustion engine, on stored electrical power by running the electric motor, or a combination of both. However, the term “hybrids” in this specification also covers vehicles capable of running an internal combustion engine on alternative fuels, such as liquefied gas in place of petrol or diesel fuel, to reduce vehicle emissions. These various ways of operating a hybrid vehicle are referred to as “operating modes” henceforth.
Hybrid vehicles are viewed as a key contributor to reduction of pollution in urban areas. Nowadays, the majority of air pollution in urban areas comes directly from road traffic rather than industry. Road traffic is considered to be responsible for 25% of all emissions in Europe. Moreover, CO2, which is a major product of ICE car emissions, is a greenhouse gas. Efforts are being made to reduce air pollution and its consequent environmental impacts, especially in urban areas. These efforts include, for example, providing incentives for urban drivers to purchase and drive a hybrid vehicle rather than a conventional ICE-based car. London's congestion charge, which exempts HEVs as well as cars which emit 100 g/km or less of CO2 and which meet the Euro 5 standard for air quality, is one example. However, such incentives to date do not take account of in what operating mode vehicles are actually driven.
Thus, for drivers to run their hybrid vehicles in an operating mode which reduces pollution is of great importance to reducing the emissions of CO2 and other pollutants. The operating mode currently in use is normally set by the driver, although this may include a setting in which the vehicle selects the most appropriate operating mode automatically.
The concept of the “Smart City” is meanwhile receiving attention. This term refers to a city in which various departments and services are interconnected, and in which a large-scale network of sensors is deployed, the sensor readings being used to monitor various parameters such as traffic congestion and pollution. This enables transport and other services to be kept running smoothly and to some extent autonomously: for example traffic congestion information may be used to manage traffic lights.
One aspect of the Smart City is pollution management by, for example, restricting use of vehicles at certain times of day and/or in certain geographical zones (low-emission zones) so as to restrict the buildup of pollutants in the air. This is referred to henceforth as a pollution management system. A conceivable pollution management system might, for example, involve vehicle recognition linked to a database of pollution levels for different types (makes and models) of vehicle. In this way, a driver of a highly-polluting vehicle might find themselves barred from entering a low-emission zone at least during certain periods. Alternatively, it is possible to envisage systems which do not simply either bar or allow certain types of vehicles, but allow many (or even most) vehicles to be driven, provided they operate in a certain mode and/or the driver/owner pays an appropriate fee (below referred to as an “emission charge”). This will give the citizens a greater freedom and flexibility without compromising the environment. Embodiments to be described later will focus on a pollution management system of this type, where vehicle usage is influenced by pricing rather than by barring certain vehicles outright.
With the proliferation of hybrid vehicles (vehicles that use a mixture of power or fuel sources), the distribution of pollution contributions from various makes of cars becomes increasingly variable. If pollution management is to adapt to this trend, it will no longer be sufficient to simply match a vehicle to a single pollution category based on the automated recognition of its number plates at the designated check point (usually a point of entry into a pollution-critical area).
Design of a potential solution is complicated by the fact that various hybrids will contribute a widely varying degree of pollutants depending on the mode they are operating in (dropping down to no pollutants at all when they are operating in an electric-only mode, as in the case of HEVs). It is important to be able to control, or levy financial charges for, vehicle usage based on which operating mode vehicles are actually being driven in, rather than based on the theoretical benefits of an operating mode which might be used only rarely.
Techniques have been proposed for remotely determining vehicle emissions from moving vehicles. Until now, however, there has been no consideration of the various operating modes available to hybrid vehicles, or for providing a pollution management solution which takes such operating modes into account.